Psychiatrist Denny Bursboom and others have proposed a network theory of mental illness which makes departs from conventional ideas about the relationship between a collection of symptoms and an underlying disorder.

The conventional idea is that symptoms are caused by a disease, and that our ultimate goal should be treatment of the latter. For example, if you have a bacterial infection, this might be causing fever, pain, and fatigue. It would not be a good idea to address this health problem by taking Advil and coffee. Even though this would eliminate the symptoms, the underlying problems would remain.

According to Borsboom, the conventional model is problematic in complex conditions that have multiple causes. For example, depression and anxiety are notoriously linked to a host of other negative symptoms, including fatigue, insomnia, pain, and addiction. When all these symptoms cluster together, what exactly is the underlying disorder?

For example, anxiety can make you socially avoidant, which leads to loneliness, which causes depression, which makes you drink, which makes it harder to do your job, which makes you anxious, which makes it harder to sleep, which makes you tired, so you can't work out, so you gain weight, and you become more anxious. So now obesity, alcoholism, anxiety, insomnia, unemployment and depression are clustering together, one reinforcing the other. What is the "real" problem causing all these others? Your Mom? Your genes? Everything in the Universe?

According to Boorsboom, the problem is not some hidden X factor causing all the symptoms. Instead, it’s the way the symptoms mutually support one another in a network of relationships.

Thus, the network itself is the disease, and the goal of treatment is to destabilize it by eliminating one or more its key "nodes." Some of the "nodes" in the network may play more of a central connecting role than others. Imagine a network of friends who all get together on a regular basis. Perhaps there is one friend who is the "glue" holding them all together. As soon as she leaves town, the group falls apart. Or maybe the group is more stable because everyone is close friends with everyone else.

A social media network. Where are the key nodes holding it together?

In the case of a mental illness, the key node connecting all the problems might be failure to get enough sleep, or not having a job. In this case, treating this one symptom might help treat the whole "disease."

I think these concepts can be applied to treat chronic pain, which is properly understood as being multi-causal, and involving similar networks of pathological relationships, including many of the exact symptoms discussed above.

For example, pain lowers mood, which reduces physical activity, which leads to poor sleep, which feeds anxiety, which leads to catastrophising, which reduces physical activity, which leads to deconditioning, etc. By eliminating one or more of these nodes on the network, maybe it the whole thing can be broken up.

Thus, many people can treat their chronic pain by improving their exercise, sleep, stress management, cognition and fear, even though an "issue in the tissue" is never identified. Practitioners with a more biomedical orientation might think this treatment plan will fail because it does not identify the underlying disease, the true prime mover for the pain. But if the pain is sufficiently complex, this search for an underlying disorder is not only unnecessary, but perhaps impossible. In other words, maybe it is true that pain is sometimes a tip with no iceberg.